Artificial leg



` Dec.5,1933. WT. CARNES K 1,937,870

ARTIFICIAL LEG Filed April 14, 1950 Bnvcntor 94./ Thrfzes Patented Dec. 5, 1.933 A ENT .OFFICE v ARTIFICIAL LEG Application April 14,1930. serialNoAinot-r 7 Claims.

, This invention relates to artificial limbs; One ofthe objects of the invention is to produce'an artificial foot capable ofsimulating all movements i which occurwith the natural foot in walking, and which avoids the transmission of shock to the stump in the event the wearers weight is imposed suddenly on the foot, which operatesnoiselessly or without `sc lueaks, is waterproof, and is of light weight yet strongand durable.

With this general object in view, the invention `consists incertain novel and useful features of construction and combinations of partsas hereinafter describedand claimed; and in order that it may be vfully understood, reference is tobe had to the accompanying drawingin which:

, `Figure 1 is a central vertical.V longitudinal section of an articial foot-embodying the invention. i f, i

Figure 2 is a horizontal i section onftheline zo IX-IX of Figure". 1, with sheath omitted. i i

Figure 3 is a vertical section taken onthe line X- X of Figure 1. p t p Figure 4 is an inverted planview of the shank f or lower legportion.

Figure 5 isa detail perspective view of the metal wear plate of/the upper member of theankle joint. Figure 6 is an `inverted plan view ofk a plate forming the top ofthe `body portionof the foot andalso forming the socketportion of the` ankle joint.

Figure 7 is a top oi?,` the foot. ,Y 7;

Referring now to the drawingy it will-be noted that the lower Vleg portion 1 is hollow `and terminates in a reduced depending portion providing a downwardly-facing shoulder 22 andthe lower leg portion is provided with a downwardlyplan view of thesole plate flaring` opening 23` nearits rear periphery and forward thereof with a `depending hemispherical ankle-jointipor'tion 24. 'The lower leg portion 1 isgenerallyhollow for lightness, is preferably of wood or equivalentmaterial, and the hemispherical ankle-joint portion has a correspondingly i centrically of .the ankle-joint portion, the in- `A ternal diameter of the cup being somewhat larger than the external diameter of the metal sheath 25, and containing a leather or equivalent lining 27 so that the ankle-joint movements may occur without the noise or squeak that might be attendant upon a metal to metal contact, especially if the `foot has become slightly wornv after a long period of service. i

The metal cup portion of the ankle-joint ts in a corresponding depression provided in a felt or equivalent compressible foot portion 28 which is flat atits upper side rearward of the ankle-joint and normally stands in a rearwardly diverging relation to the opposing overlying end of the Vleg portion. The metal cupis provided with a rearward extension 29,1itting down upon the ilat upper portion of the foot and with a downwardly and `forwardly extending front portion 30 fitting squarely upon the foot portion overI what may be termed the instep thereof i and terminating slightly short of the plane of the metatarsus joint of the natural foot, and the marginal portion of the metal plate is provided` with a depending ange 31 which extends completely around `the plate except` at its front end, and `said plate including the cup portion is preferably vulcanized to the compressible `or felt foot portion. The `flat rear portion 29 is provided with an opening 32 registering with a vertical opening 33 in the foot portion. A Y

A sole plate 34 of metal or equivalent material underlies the rear half of the foot and is anged upward Inarginallyat 35, except at its lfront extremity, to snugly receive the overlying portion of the foot and heel portion thereof, and said plate is provided with an opening 36 and with two inverted V-shaped spaced bearing lugs 37 projecting up into the foot portion, the space between said lugs coinciding or registering with the opening 33, and fitting in said bearing lugs is a cross pin 38 to which the lower `end of a non-elastic but iiexible cord 39 is attaclfled,V the said cord extending up throughopenings 33, 32 and 23,` and being secured at its upper end to across pin 40 secured in the leg portion, the arrangement bef ing such that the cord substantially limits ;fo1 ward hinge movement of the leg portion relative to the foot portion and at the same timepermits of `limited `lateral rocking and twisting or rotarymovement of the leg portionrelative to i might occur when the wearer steps down from an elevated point, as in coming down a stairway or the like. In such action it is intended that the excessive force applied upon the joint shall be absorbed by a gradual compression of the foot portion.

The front end of the sole plate, if not cemented or perhaps even if cemented to the foot portion is preferably fastened to the latter `by one or more rivets or screws 4l, the upper heads of the rivets or screws being countersunk in the foot portion.

A shoe 42 of rubber fabric or the like possessing great resilience and at the same time utility and durability and of course water-excluding properties, snugly fits upon the foot portion and is preferably vulcanized to the exposed felt or compressible portion thereof, and the upper or ankle portion of the shoe, snugly embraces the lower part or reduced extension of the leg portion and abuts at its upper end against the downwardly-facing shoulder Y22 thereof, the contacting portions of the shoe and leg portion being fastened together with a water-proof cement, so that it shall be impossible for water to enter between the upper end of the shoev and the shoulder 22 and thus obtain access to the metal portions and to the cord 39 with the possibility of corrosion of the former and impairment of the eiiiciency and strength of the latter.

If the wearer happens to step on an uneven or irregular surface, the cushioning body portion of the foot will yield to avoid danger of a fall, and it will yield laterally as well as longitudinallyby reason of the ball and'socket ankle-joint and the rubber shoe, the latter in conjunction with the cord 39 holding the ankle-joint members against relative dislocation so that no undue play or movement of the foot is permitted. At the same-time the ankle-joint parts are held rmly together so as to avoid lost motion and the consequent'shock or jar on the stump of the leg in the event the wearer in stepping down or otherwise throws his weight forcibly upon the artificial foot. The rubber shoe not only possesses the advantage mentioned and the other advantage of making the foot waterproof, but also, through its resiliency, assists in restoring the toe portion of the foot to normal position-after each bending operation thereof, as it is a common fault of the ordinary compressible foot after absorbing water followed by repeated bending operations, to retain its bent position, which is objectionable from an aesthetic point of view,- and also because lacking life becomes inefiicient in the performance of cushioning functions.

From the above description, it will be apparent that I have produced an artificial leg embodying the features of advantage set forth as desirable in the statement of the objects of the invention, and which is susceptible' of modification in various particulars without departing from the principle of construction and mode of operation involved or vfrom the spirit and scope of the appended claims.

I claim:

1. In an artificial limb, a leg portion having a depending portion terminating at its lower end forward of its rear edge in aV hemispherical projecti'om a correspondingly shaped wear plate on said projection and secured in rigid relation thereto, a foot portion having a conforming cavity or depression receiving said projection anda corresponding wear plate lining, a conforming compressible lining interposed between the firstnamed and last-named wear plates; the lastnamed plate having front and rear portions fitting flatly upon the instep and top of the heel portions of the foot and provided with depending flanges engaging the side and rear edges of the foot, a sole plate underlying the rear half of the foot and provided with an upstanding marginal flange externally engaging the sides and rear end of the foot.

2. In an artificial limb, a leg portion having a depending hemispherical projection, a correspondingly shaped wear plate thereon, a foot portion having a conforming cavity or depression and a corresponding wear plate lining, and a conforming compressible lining interposed between the first-named and last-named wear plates; said wear plate lining of the foot portion having forwardrand rearward extensions resting flatly upon the foot portion and provided with a depending marginal flange running around the sides of said extensions and the rear end of the rear extension, Va plate underlying the instep portion and heel of the foot portion, a cord extending up through the foot portion and the overlying plate extension and into the leg portion and ,100

anchored at its lower end to the plate underlying the foot portion and at its upper end within the leg portion, and a resilient shoe completely Vencasing the foot portion and said underlying plate and the lower part of the leg portion 'and offering resistance to downward movement of the latter independent of the foot portion; said shoe being vulcanized to the foot portion andv cemented at its upper end, to the leg-portion,

3. An artificial limb, comprising a lower 'leg portion and a foot portion having a universal ankle-joint connection, and van upright non-elastic iiexible cord connection back-of the 'anklejoint connection, the foot-portion consisting of compressible material; and va lresilient shoeshaped sheath `enclosing the foot portion and the and the bottom of the rear'half of the foot'portion, the last-named plate being connected *to and forming a lower anchorage for the'I cord.

4. An artificial limb, comprising a-'lower leg portion-and a foot portion having a universal ankle-joint connection-and anupright non-elastic flexiblev cord connection back of the anklejoint connection, the foot-portion `consistingof compressible material, and a resilient shoeshaped sheath enclosing thefoot portion and the lower part of the leg portion and bearingat .its upper end against' the latter to yieldingly resist changes of angular relation between'it andthe foot portion, the cord connection vsubstantially limiting forward bend of the leg portion relative to thev foot portion and undue stretching of tle resilient shoe or sheath,-and a pairof hard-material plates respectively covering-the top of `the foot portion around theankle-joint connection, and the bottom of the rear. half ofthefootfportion, the last-named plate beingconnecteditoJand forming a lower anchorage for the cord, .and means for" holding Athe frontl portion=of 'theA lastnamed plate likhtly againstA the -foot portionv'tov protect the underlying portion of the resilient shoe. l

5. A metal plate of elongated type having a rounded rear end, the plate comprising front and rear portions relatively disposed to form an obtuse angle, the rear portion having an opening and also having `a depending semi-spherical socket portion open at the upper side of the plate and disposed in close proximity to the front portionof the plate and forward of said opening, a heel plate below and generally parallel to the iirst-named plate, and a compressible foot iitting snugly between and secured to said plates and n receiving the socket portion of the first-named plate and provided with an opening alined with the opening of the latter.

6. The combination of a leg portion orhard material and a foot portion of compressible material, and an universal ball-joint connection between the lower end of the leg portion and the upper part of the foot portion,V a top plate tting flatly upon the top of the foot portion forward, rearward and at both sides of and integral with the socket portion oi. the joint and provided around its rear end and sides with depending anges exteriorly` engaging the corresponding surfaces of the foot portion, and a plate fitting flatly against the underside of the foot portion and provided with upstanding iianges engaging the proximate exterior surface of the heel portion of the foot.

7. The combination of a leg portion of hard material and a foot portion of compressible ma.- terial, and an universal ball-joint connection between the lower end of the leg portion and the upper part of the foot portion, a top plate fitting flatly upon the top of the foot portion for. 

